Through extensive travel and extreme reliability, these spacecraft revealed many answers while setting the stage for further exploration of the outer solar system. .
Pioneer 10 was launched on March 2, 1972 and was the first spacecraft to encounter Jupiter. At a speed of 32,400 mph, Pioneer 10 sped towards its rendezvous with our Solar System's largest plant. This made Pioneer 10 the fastest manmade object to leave earth. After maneuvering through the Asteroid Belt and, the spacecraft closed to within 81,000 miles of Jupiter. In its passing of Jupiter, Pioneer 10 gathered the first close-up images of the planet while charting its intense radiation belts. It also located the planets magnetic field and discovered that Jupiter is mostly composed of liquid. After gaining data from Jupiter, Pioneer 10 continued to the outer regions of the Solar system studying Solar Wind and cosmic rays which enter our side of the Milky Way. This spacecraft continued investigating the outer areas of the solar system until its mission ended on March 31, 1997. Although the mission had ended, NASA continued to attempt contact with the spacecraft in which its last transmission was received on earth on February 7th 2003. These transmissions were merely communication links, for the spacecraft's power supply had degraded to the point that no telemetry (scientifically measured) data could be produced. The last telemetry data transmission by Pioneer 10 occurred on April 27, 2002 (1). Although no further contact is expected, Pioneer 10 is now on a path heading towards the red star Aldebaran, which forms the eye of the constellation Taurus. Aldebaran is approximately 68 light years away and it will take Pioneer over 2 million years to arrive at this destination (4). Pioneer 10 is now over 7.5 billion miles away from the Sun and on June 13, 1983 became the first manmade object to leave the Solar System (3).